I ran the update from Garmin Express on my Zumo 660 for new maps and software, but I guess a file got corrupted somehow and now it freezes with "loader loading" on the screen. Computer doesn't see the unit. Has anyone had/solved this issue? There is a procedure on line for a Nuvi but it doesn't work for Zumo (tried every possible variation - no luck). Tried removing the battery for 10 minutes, holding the on/off switch down etc. Apparently you have to get the unit into "mass storage" mode so you can delete the corrupted file from your computer, then re-install the update. Any help would be much appreciated!!!